Tag Archives: buckyballs

Artificial graphene with buckyballs

A July 21, 2022 news item on Nanowerk describes graphene in its ‘natural’ state and explains what ‘artificial’ graphene is although there is no mention of why variants are a hot topic,

Graphene consists of carbon atoms that crosslink in a plane to form a flat honeycomb structure. In addition to surprisingly high mechanical stability, the material has exciting electronic properties: The electrons behave like massless particles, which can be clearly demonstrated in spectrometric experiments.

Measurements reveal a linear dependence of energy on momentum, namely the so-called Dirac cones – two lines that cross without a band gap – i.e. an energy difference between electrons in the conduction band and those in the valence bands.

Variants in graphene architecture

Artificial variants of graphene architecture are a hot topic in materials research right now. Instead of carbon atoms, quantum dots of silicon have been placed, ultracold atoms have been trapped in the honeycomb lattice with strong laser fields, or carbon monoxide molecules have been pushed into place on a copper surface piece by piece with a scanning tunneling microscope, where they could impart the characteristic graphene properties to the electrons of the copper.

A July 21, 2022 Helmholtz-Zentrum Berlin (HZB) press release (also on EurekAlert), which originated the news item, describes research into whether or not layering buckyballs onto gold would result in artificial graphene,

Artificial graphene with buckyballs?

A recent study suggested that it is infinitely easier to make artificial graphene using C60 molecules called buckyballs [or buckminsterfullerenes or, more generically, fullerenes]. Only a uniform layer of these needs to be vapor-deposited onto gold for the gold electrons to take on the special graphene properties. Measurements of photoemission spectra appeared to show a kind of Dirac cone.

Analysis of band structures at BESSY II

“That would be really quite amazing,” says Dr. Andrei Varykhalov, of HZB, who heads a photoemission and scanning tunneling microscopy group. “Because the C60 molecule is absolutely nonpolar, it was hard for us to imagine how such molecules would exert a strong influence on the electrons in the gold.” So Varykhalov and his team launched a series of measurements to test this hypothesis.

In tricky and detailed analyses, the Berlin team was able to study C60 layers on gold over a much larger energy range and for different measurement parameters. They used angle-resolved ARPES spectroscopy at BESSY II [third-generation synchrotron radiation source], which enables particularly precise measurements, and also analysed electron spin for some measurements.

Normal behavior

“We see a parabolic relationship between momentum and energy in our measured data, so it’s a very normal behavior. These signals come from the electrons deep in the substrate (gold or copper) and not the layer, which could be affected by the buckyballs,” explains Dr. Maxim Krivenkov, lead author of the study. The team was also able to explain the linear measurement curves from the previous study. “These measurement curves merely mimic the Dirac cones; they are an artifact, so to speak, of a deflection of the photoelectrons as they leave the gold and pass through the C60 layer,” Varykhalov explains. Therefore, the buckyball layer on gold cannot be considered an artificial graphene.

Caption: Measurement data from BESSY II before and after deposition of C60 molecules demonstrate the replication of the band structure and the emergence of cone-like band crossings. A scanning electron microscopy of the buckyballs on gold is superimposed in the centre. Credit: HZB

Here’s a link to and a citation for the paper,

On the problem of Dirac cones in fullerenes on gold by M. Krivenkov, D. Marchenko, M. Sajedi, A. Fedorov, O. J. Clark, J. Sánchez-Barriga, E. D. L. Rienks, O. Rader and A. Varykhalov. Nanoscale, 2022,14, 9124-9133 First published: 23 May 2022

This paper is open access.

Could buckyballs and carbon nanotubes come from the dust and gas of dying stars?

In this picture of the Spirograph Nebula, a dying star about 2,000 light-years from Earth, NASA’s Hubble Space Telescope revealed some remarkable textures weaving through the star’s envelope of dust and gas. UArizona researchers have now found evidence that complex carbon nanotubes could be forged in such environments.. Credit: NASA and The Hubble Heritage Team (STScI/AURA)

It’s always interesting to come across different news releases announcing the same research. In this case I have two news releases, one from the US National Science Foundation (NSF) and one from the University of Arizona. Let’s start with the July 19, 2022 news item on phys.org (originated by the US NSF),

Astronomers at the University of Arizona have developed a theory to explain the presence of the largest molecules known to exist in interstellar gas.

The team simulated the environment of dying stars and observed the formation of buckyballs (carbon atoms linked to three other carbon atoms by covalent bonds) and carbon nanotubes (rolled up sheets of single-layer carbon atoms). The findings indicate that buckyballs and carbon nanotubes can form when silicon carbide dust — known to be proximate to dying stars — releases carbon in reaction to intense heat, shockwaves and high energy particles.

Here’s the rest of the July 18, 2022 NSF news release, Note: A link has been removed,

“We know from infrared observations that buckyballs populate the interstellar medium,” said Jacob Bernal, who led the research. “The big problem has been explaining how these massive, complex carbon molecules could possibly form in an environment saturated with hydrogen, which is what you typically have around a dying star.”

Rearranging the structure of graphene (a sheet of single-layer carbon atoms) could create buckyballs and nanotubes. Building on that, the team heated silicon carbide samples to temperatures that would mimic the aura of a dying star and observed the formation of nanotubes.

“We were surprised we could make these extraordinary structures,” Bernal said. “Chemically, our nanotubes are very simple, but they are extremely beautiful.”

Buckyballs are the largest molecules currently known to occur in interstellar space. It is now known that buckyballs containing 60 to 70 carbon atoms are common.

“We know the raw material is there, and we know the conditions are very close to what you’d see near the envelope of a dying star,” study co-author Lucy Ziurys said. “Shock waves pass through the envelope, and the temperature and pressure conditions have been shown to exist in space. We also see buckyballs in planetary nebulae — in other words, we see the beginning and the end products you would expect in our experiments.”

A June 16, 2022 University of Arizona news release by Daniel Stolte (also on EurekAlert) takes a context-rich approach to writing up the proposed theory for how buckyballs and carbon nanotubes (CNTs) form (Note: Links have been removed),

In the mid-1980s, the discovery of complex carbon molecules drifting through the interstellar medium garnered significant attention, with possibly the most famous examples being Buckminsterfullerene, or “buckyballs” – spheres consisting of 60 or 70 carbon atoms. However, scientists have struggled to understand how these molecules can form in space.

In a paper accepted for publication in the Journal of Physical Chemistry A, researchers from the University of Arizona suggest a surprisingly simple explanation. After exposing silicon carbide – a common ingredient of dust grains in planetary nebulae – to conditions similar to those found around dying stars, the researchers observed the spontaneous formation of carbon nanotubes, which are highly structured rod-like molecules consisting of multiple layers of carbon sheets. The findings were presented on June 16 [2022] at the 240th Meeting of the American Astronomical Society in Pasadena, California.

Led by UArizona researcher Jacob Bernal, the work builds on research published in 2019, when the group showed that they could create buckyballs using the same experimental setup. The work suggests that buckyballs and carbon nanotubes could form when the silicon carbide dust made by dying stars is hit by high temperatures, shock waves and high-energy particles, leaching silicon from the surface and leaving carbon behind.

The findings support the idea that dying stars may seed the interstellar medium with nanotubes and possibly other complex carbon molecules. The results have implications for astrobiology, as they provide a mechanism for concentrating carbon that could then be transported to planetary systems.

“We know from infrared observations that buckyballs populate the interstellar medium,” said Bernal, a postdoctoral research associate in the UArizona Lunar and Planetary Laboratory. “The big problem has been explaining how these massive, complex carbon molecules could possibly form in an environment saturated with hydrogen, which is what you typically have around a dying star.”

The formation of carbon-rich molecules, let alone species containing purely carbon, in the presence of hydrogen is virtually impossible due to thermodynamic laws. The new study findings offer an alternative scenario: Instead of assembling individual carbon atoms, buckyballs and nanotubes could result from simply rearranging the structure of graphene – single-layered carbon sheets that are known to form on the surface of heated silicon carbide grains.

This is exactly what Bernal and his co-authors observed when they heated commercially available silicon carbide samples to temperatures occurring in dying or dead stars and imaged them. As the temperature approached 1,050 degreesCelsius, small hemispherical structures with the approximate size of about 1 nanometer were observed at the grain surface. Within minutes of continued heating, the spherical buds began to grow into rod-like structures, containing several graphene layers with curvature and dimensions indicating a tubular form. The resulting nanotubules ranged from about 3 to 4 nanometers in length and width, larger than buckyballs. The largest imaged specimens were comprised of more than four layers of graphitic carbon. During the heating experiment, the tubes were observed to wiggle before budding off the surface and getting sucked into the vacuum surrounding the sample.

“We were surprised we could make these extraordinary structures,” Bernal said. “Chemically, our nanotubes are very simple, but they are extremely beautiful.”

Named after their resemblance to architectural works by Richard Buckminster Fuller, fullerenes are the largest molecules currently known to occur in interstellar space, which for decades was believed to be devoid of any molecules containing more than a few atoms, 10 at most. It is now well established that the fullerenes C60 and C70, which contain 60 or 70 carbon atoms, respectively, are common ingredients of the interstellar medium.

One of the first of its kind in the world, the transmission electron microscope housed at the Kuiper Materials Imaging and Characterization Facility at UArizona is uniquely suited to simulate the planetary nebula environment. Its 200,000-volt electron beam can probe matter down to 78 picometers – the distance of two hydrogen atoms in a water molecule – making it possible to see individual atoms. The instrument operates in a vacuum closely resembling the pressure – or lack thereof – thought to exist in circumstellar environments.

While a spherical C60 molecule measures 0.7 nanometers in diameter, the nanotube structures formed in this experiment measured several times the size of C60, easily exceeding 1,000 carbon atoms. The study authors are confident their experiments accurately replicated the temperature and density conditions that would be expected in a planetary nebula, said co-author Lucy Ziurys, a UArizona Regents Professor of Astronomy, Chemistry and Biochemistry.

“We know the raw material is there, and we know the conditions are very close to what you’d see near the envelope of a dying star,” she said. “There are shock waves that pass through the envelope, so the temperature and pressure conditions have been shown to exist in space. We also see buckyballs in these planetary nebulae – in other words, we see the beginning and the end products you would expect in our experiments.”

These experimental simulations suggest that carbon nanotubes, along with the smaller fullerenes, are subsequently injected into the interstellar medium. Carbon nanotubes are known to have high stability against radiation, and fullerenes are able to survive for millions of years when adequately shielded from high-energy cosmic radiation. Carbon-rich meteorites, such as carbonaceous chondrites, could contain these structures as well, the researchers propose.

According to study co-author Tom Zega, a professor in the UArizona Lunar and Planetary Lab, the challenge is finding nanotubes in these meteorites, because of the very small grain sizes and because the meteorites are a complex mix of organic and inorganic materials, some with sizes similar to those of nanotubes.

“Nonetheless, our experiments suggest that such materials could have formed in interstellar space,” Zega said. “If they survived the journey to our local part of the galaxy where our solar system formed some 4.5 billion years ago, then they could be preserved inside of the material that was left over.”

Zega said a prime example of such leftover material is Bennu, a carbonaceous near-Earth asteroid from which NASA’s UArizona-led OSIRIS-REx mission scooped up a sample in October 2020. Scientists are eagerly awaiting the arrival of that sample, scheduled for 2023.  

“Asteroid Bennu could have preserved these materials, so it is possible we may find nanotubes in them,” Zega said.

Here’s a link to and a citation for the paper,

Destructive Processing of Silicon Carbide Grains: Experimental Insights into the Formation of Interstellar Fullerenes and Carbon Nanotubes by Jacob J. Bernal, Thomas J. Zega, and Lucy M. Ziurys. J. Phys. Chem. A 2022, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acs.jpca.2c01441 Publication Date:June 27, 2022 © 2022 American Chemical Society

This paper is behind a paywall.

Artificial intelligence (AI) designs “Giants of Nanotech” non-fungible tokens (NFTs)

Nanowerk, an agency which provides nanotechnology information and more, has commissioned a series of AI-designed non-fungible tokens representing two of the ‘Giants of Nanotechnology’, Richard Feynman and Sir Harold Kroto.

It’s a fundraising effort as noted here in an April 10, 2022 Nanowerk Spotlight article by website owner, Michael Berger,

We’ve spent a lot of time recently researching and writing the articles for our Smartworlder section here on Nanowerk – about cryptocurrencies, explaining blockchain, and many other aspects of smart technologies – for instance non-fungible tokens (NFTs). So, we thought: Why not go all the way and try this out ourselves?

As many organizations continue to push the boundaries as to what is possible within the web3 ecosystem, producing our first-ever collection of nanotechnology-themed digital art on the blockchain seemed like a natural extension for our brand and we hope that these NFT collectibles will be cherished by our reader community.

To start with, we created two inaugural Nanowerk NFT collections in a series we are calling Giants of Nanotech in order to honor the great minds of science in this field.

The digital artwork has been created using the artificial intelligence (AI) image creation algorithm Neural Style Transfer. This technique takes two images – a content image and a style reference image (such as an artwork by a famous painter) – and blends them together so the output image looks like the content image, but ‘painted’ in the style of the reference image.

For example, here is a video clip that shows how the AI transforms the Feynman content image into a painting inspired by Victor Nunnally’s Journey Man:

If you want to jump right into it, here are the Harry Kroto collection and the Richard Feynman collection on the OpenSea marketplace.

Have fun with our NFTs and please remember, your purchase helps fund Nanowerk and we are very grateful to you!

Also note: NFTs are an extremely volatile market. This article is not financial advice. Invest in the crypto and NFT market at your own risk. Only invest if you fully understand the potential risks.

I have a couple of comments. First, there’s Feynman’s status as a ‘Giant of Nanotechnology’. He is credited in the US as providing a foundational text (a 1959 lecture titled “There’s Plenty of Room at the Bottom”) for the field of nanotechnology. There has been some controversy over the lecture’s influence some of which has been covered in the Wikipedia entry titled, “There’s Plenty of Room at the Bottom.”

Second, Sir Harold Kroto won the 1996 Nobel Prize for Chemistry, along with two colleagues (all three were at Rice University in Texas), for the discovery of the buckminsterfullerene. Here’s more about that from the Richard E. Smalley, Robert F. Curl, and Harold W. Kroto essay on the Science History Institute website,

In 1996 three scientists, two American and one British, shared the Nobel Prize in Chemistry for their discovery of buckminsterfullerene (the “buckyball”) and other fullerenes. These “carbon cages” resembling soccer balls opened up a whole new field of chemical study with practical applications in materials science, electronics, and nanotechnology that researchers are only beginning to uncover.

With their discovery of buckminsterfullerene in 1985, Richard E. Smalley (1943–2005), Robert F. Curl (b. 1933), and Harold W. Kroto (1939–2016) furthered progress to the long-held objective of molecular-scale electronics and other nanotechnologies. …

Finally, good luck to Nanowerk and Michael Berger.

Interstellar buckyball mystery solved

Caption: An artist’s conception showing spherical carbon molecules known as buckyballs coming out from a planetary nebula — material shed by a dying star. Researchers at the University of Arizona have now created these molecules under laboratory conditions thought to mimic those in their ‘natural’ habitat in space. Credit: NASA/JPL-Caltech

A ‘buckyball’, for anyone who doesn’t know, is a molecule made up of carbon atoms, Said to resemble soccer balls or geodesic domes, they’re also known as C60 or Buckminsterfullerenes as Rachel Abraham notes in her November 13, 2019 University of Arizona news release (also on EurekAlert),

Scientists have long been puzzled by the existence of so-called “buckyballs” – complex carbon molecules with a soccer-ball-like structure – throughout interstellar space. Now, a team of researchers from the University of Arizona has proposed a mechanism for their formation in a study published in the Astrophysical Journal Letters.

Carbon 60, or C60 for short, whose official name is Buckminsterfullerene, comes in spherical molecules consisting of 60 carbon atoms organized in five-membered and six-membered rings. The name “buckyball” derives from their resemblance to the architectural work of Richard Buckminster Fuller [bettr known as Buckminster Fuller], who designed many dome structures that look similar to C60. Their formation was thought to only be possible in lab settings until their detection in space challenged this assumption.

For decades, people thought interstellar space was sprinkled with lightweight molecules only: mostly single atoms, two-atom molecules and the occasional nine or 10-atom molecules. This was until massive C60 and C70 molecules were detected a few years ago.

Researchers were also surprised to find that that they were composed of pure carbon. In the lab, C60 is made by blasting together pure carbon sources, such as graphite. In space, C60 was detected in planetary nebulae, which are the debris of dying stars. This environment has about 10,000 hydrogen molecules for every carbon molecule.

“Any hydrogen should destroy fullerene synthesis,” said astrobiology and chemistry doctoral student Jacob Bernal, lead author of the paper. “If you have a box of balls, and for every 10,000 hydrogen balls you have one carbon, and you keep shaking them, how likely is it that you get 60 carbons to stick together? It’s very unlikely.”

Bernal and his co-authors began investigating the C60 mechanism after realizing that the transmission electron microscope, or TEM, housed at the Kuiper Materials Imaging and Characterization Facility at UArizona, was able to simulate the planetary nebula environment fairly well.

The TEM, which is funded by the National Science Foundation and NASA, has a serial number of “1” because it is the first of its kind in the world with its exact configuration. Its 200,000-volt electron beam can probe matter down to 78 picometers – scales too small for the human brain to comprehend – in order to see individual atoms. It operates under a vacuum with extremely low pressures. This pressure, or lack thereof, in the TEM is very close to the pressure in circumstellar environments.

“It’s not that we necessarily tailored the instrument to have these specific kinds of pressures,” said Tom Zega, associate professor in the UArizona Lunar and Planetary Lab and study co-author. “These instruments operate at those kinds of very low pressures not because we want them to be like stars, but because molecules of the atmosphere get in the way when you’re trying to do high-resolution imaging with electron microscopes.”

The team partnered with the U.S. Department of Energy’s Argonne National Lab, near Chicago, which has a TEM capable of studying radiation responses of materials. They placed silicon carbide, a common form of dust made in stars, in the low-pressure environment of the TEM, subjected it to temperatures up to 1,830 degrees Fahrenheit and irradiated it with high-energy xenon ions.

Then, it was brought back to Tucson for researchers to utilize the higher resolution and better analytical capabilities of the UArizona TEM. They knew their hypothesis would be validated if they observed the silicon shedding and exposing pure carbon.

“Sure enough, the silicon came off, and you were left with layers of carbon in six-membered ring sets called graphite,” said co-author Lucy Ziurys, Regents Professor of astronomy, chemistry and biochemistry. “And then when the grains had an uneven surface, five-membered and six-membered rings formed and made spherical structures matching the diameter of C60. So, we think we’re seeing C60.”

This work suggests that C60 is derived from the silicon carbide dust made by dying stars, which is then hit by high temperatures, shockwaves and high energy particles , leeching silicon from the surface and leaving carbon behind. These big molecules are dispersed because dying stars eject their material into the interstellar medium – the spaces in between stars – thus accounting for their presence outside of planetary nebulae. Buckyballs are very stable to radiation, allowing them to survive for billions of years if shielded from the harsh environment of space.

“The conditions in the universe where we would expect complex things to be destroyed are actually the conditions that create them,” Bernal said, adding that the implications of the findings are endless.

“If this mechanism is forming C60, it’s probably forming all kinds of carbon nanostructures,” Ziurys said. “And if you read the chemical literature, these are all thought to be synthetic materials only made in the lab, and yet, interstellar space seems to be making them naturally.”

If the findings are any sign, it appears that there is more the universe has to tell us about how chemistry truly works.

I have two links and citations. This first is for the 2019 paper being described here and the second is the original 1985 paper about C60.

Formation of Interstellar C60 from Silicon Carbide Circumstellar Grains by J. J. Bernal, P. Haenecour, J. Howe, T. J. Zega, S. Amari, and L. M. Ziurys. The Astrophysical Journal Letters, Volume 883, Number 2 Published 2019 October 1 © 2019. The American Astronomical Society. All rights reserved.

This paper is behind a paywall.

C60: Buckminsterfullerene by H. W. Kroto, J. R. Heath, S. C. O’Brien, R. F. Curl & R. E. Smalley. Nature volume 318, pages162–163 (1985) doi:10.1038/318162a0

This paper is open access.

It’s a very ‘carbony’ time: graphene jacket, graphene-skinned airplane, and schwarzite

In August 2018, I been stumbled across several stories about graphene-based products and a new form of carbon.

Graphene jacket

The company producing this jacket has as its goal “… creating bionic clothing that is both bulletproof and intelligent.” Well, ‘bionic‘ means biologically-inspired engineering and ‘intelligent‘ usually means there’s some kind of computing capability in the product. This jacket, which is the first step towards the company’s goal, is not bionic, bulletproof, or intelligent. Nonetheless, it represents a very interesting science experiment in which you, the consumer, are part of step two in the company’s R&D (research and development).

Onto Vollebak’s graphene jacket,

Courtesy: Vollebak

From an August 14, 2018 article by Jesus Diaz for Fast Company,

Graphene is the thinnest possible form of graphite, which you can find in your everyday pencil. It’s purely bi-dimensional, a single layer of carbon atoms that has unbelievable properties that have long threatened to revolutionize everything from aerospace engineering to medicine. …

Despite its immense promise, graphene still hasn’t found much use in consumer products, thanks to the fact that it’s hard to manipulate and manufacture in industrial quantities. The process of developing Vollebak’s jacket, according to the company’s cofounders, brothers Steve and Nick Tidball, took years of intensive research, during which the company worked with the same material scientists who built Michael Phelps’ 2008 Olympic Speedo swimsuit (which was famously banned for shattering records at the event).

The jacket is made out of a two-sided material, which the company invented during the extensive R&D process. The graphene side looks gunmetal gray, while the flipside appears matte black. To create it, the scientists turned raw graphite into something called graphene “nanoplatelets,” which are stacks of graphene that were then blended with polyurethane to create a membrane. That, in turn, is bonded to nylon to form the other side of the material, which Vollebak says alters the properties of the nylon itself. “Adding graphene to the nylon fundamentally changes its mechanical and chemical properties–a nylon fabric that couldn’t naturally conduct heat or energy, for instance, now can,” the company claims.

The company says that it’s reversible so you can enjoy graphene’s properties in different ways as the material interacts with either your skin or the world around you. “As physicists at the Max Planck Institute revealed, graphene challenges the fundamental laws of heat conduction, which means your jacket will not only conduct the heat from your body around itself to equalize your skin temperature and increase it, but the jacket can also theoretically store an unlimited amount of heat, which means it can work like a radiator,” Tidball explains.

He means it literally. You can leave the jacket out in the sun, or on another source of warmth, as it absorbs heat. Then, the company explains on its website, “If you then turn it inside out and wear the graphene next to your skin, it acts like a radiator, retaining its heat and spreading it around your body. The effect can be visibly demonstrated by placing your hand on the fabric, taking it away and then shooting the jacket with a thermal imaging camera. The heat of the handprint stays long after the hand has left.”

There’s a lot more to the article although it does feature some hype and I’m not sure I believe Diaz’s claim (August 14, 2018 article) that ‘graphene-based’ hair dye is perfectly safe ( Note: A link has been removed),

Graphene is the thinnest possible form of graphite, which you can find in your everyday pencil. It’s purely bi-dimensional, a single layer of carbon atoms that has unbelievable properties that will one day revolutionize everything from aerospace engineering to medicine. Its diverse uses are seemingly endless: It can stop a bullet if you add enough layers. It can change the color of your hair with no adverse effects. [emphasis mine] It can turn the walls of your home into a giant fire detector. “It’s so strong and so stretchy that the fibers of a spider web coated in graphene could catch a falling plane,” as Vollebak puts it in its marketing materials.

Not unless things have changed greatly since March 2018. My August 2, 2018 posting featured the graphene-based hair dye announcement from March 2018 and a cautionary note from Dr. Andrew Maynard (scroll down ab out 50% of the way for a longer excerpt of Maynard’s comments),

Northwestern University’s press release proudly announced, “Graphene finds new application as nontoxic, anti-static hair dye.” The announcement spawned headlines like “Enough with the toxic hair dyes. We could use graphene instead,” and “’Miracle material’ graphene used to create the ultimate hair dye.”

From these headlines, you might be forgiven for getting the idea that the safety of graphene-based hair dyes is a done deal. Yet having studied the potential health and environmental impacts of engineered nanomaterials for more years than I care to remember, I find such overly optimistic pronouncements worrying – especially when they’re not backed up by clear evidence.

These studies need to be approached with care, as the precise risks of graphene exposure will depend on how the material is used, how exposure occurs and how much of it is encountered. Yet there’s sufficient evidence to suggest that this substance should be used with caution – especially where there’s a high chance of exposure or that it could be released into the environment.

The full text of Dr. Maynard’s comments about graphene hair dyes and risk can be found here.

Bearing in mind  that graphene-based hair dye is an entirely different class of product from the jacket, I wouldn’t necessarily dismiss risks; I would like to know what kind of risk assessment and safety testing has been done. Due to their understandable enthusiasm, the brothers Tidball have focused all their marketing on the benefits and the opportunity for the consumer to test their product (from graphene jacket product webpage),

While it’s completely invisible and only a single atom thick, graphene is the lightest, strongest, most conductive material ever discovered, and has the same potential to change life on Earth as stone, bronze and iron once did. But it remains difficult to work with, extremely expensive to produce at scale, and lives mostly in pioneering research labs. So following in the footsteps of the scientists who discovered it through their own highly speculative experiments, we’re releasing graphene-coated jackets into the world as experimental prototypes. Our aim is to open up our R&D and accelerate discovery by getting graphene out of the lab and into the field so that we can harness the collective power of early adopters as a test group. No-one yet knows the true limits of what graphene can do, so the first edition of the Graphene Jacket is fully reversible with one side coated in graphene and the other side not. If you’d like to take part in the next stage of this supermaterial’s history, the experiment is now open. You can now buy it, test it and tell us about it. [emphasis mine]

How maverick experiments won the Nobel Prize

While graphene’s existence was first theorised in the 1940s, it wasn’t until 2004 that two maverick scientists, Andre Geim and Konstantin Novoselov, were able to isolate and test it. Through highly speculative and unfunded experimentation known as their ‘Friday night experiments,’ they peeled layer after layer off a shaving of graphite using Scotch tape until they produced a sample of graphene just one atom thick. After similarly leftfield thinking won Geim the 2000 Ig Nobel prize for levitating frogs using magnets, the pair won the Nobel prize in 2010 for the isolation of graphene.

Should you be interested, in beta-testing the jacket, it will cost you $695 (presumably USD); order here. One last thing, Vollebak is based in the UK.

Graphene skinned plane

An August 14, 2018 news item (also published as an August 1, 2018 Haydale press release) by Sue Keighley on Azonano heralds a new technology for airplans,

Haydale, (AIM: HAYD), the global advanced materials group, notes the announcement made yesterday from the University of Central Lancashire (UCLAN) about the recent unveiling of the world’s first graphene skinned plane at the internationally renowned Farnborough air show.

The prepreg material, developed by Haydale, has potential value for fuselage and wing surfaces in larger scale aero and space applications especially for the rapidly expanding drone market and, in the longer term, the commercial aerospace sector. By incorporating functionalised nanoparticles into epoxy resins, the electrical conductivity of fibre-reinforced composites has been significantly improved for lightning-strike protection, thereby achieving substantial weight saving and removing some manufacturing complexities.

Before getting to the photo, here’s a definition for pre-preg from its Wikipedia entry (Note: Links have been removed),

Pre-preg is “pre-impregnated” composite fibers where a thermoset polymer matrix material, such as epoxy, or a thermoplastic resin is already present. The fibers often take the form of a weave and the matrix is used to bond them together and to other components during manufacture.

Haydale has supplied graphene enhanced prepreg material for Juno, a three-metre wide graphene-enhanced composite skinned aircraft, that was revealed as part of the ‘Futures Day’ at Farnborough Air Show 2018. [downloaded from https://www.azonano.com/news.aspx?newsID=36298]

A July 31, 2018 University of Central Lancashire (UCLan) press release provides a tiny bit more (pun intended) detail,

The University of Central Lancashire (UCLan) has unveiled the world’s first graphene skinned plane at an internationally renowned air show.

Juno, a three-and-a-half-metre wide graphene skinned aircraft, was revealed on the North West Aerospace Alliance (NWAA) stand as part of the ‘Futures Day’ at Farnborough Air Show 2018.

The University’s aerospace engineering team has worked in partnership with the Sheffield Advanced Manufacturing Research Centre (AMRC), the University of Manchester’s National Graphene Institute (NGI), Haydale Graphene Industries (Haydale) and a range of other businesses to develop the unmanned aerial vehicle (UAV), which also includes graphene batteries and 3D printed parts.

Billy Beggs, UCLan’s Engineering Innovation Manager, said: “The industry reaction to Juno at Farnborough was superb with many positive comments about the work we’re doing. Having Juno at one the world’s biggest air shows demonstrates the great strides we’re making in leading a programme to accelerate the uptake of graphene and other nano-materials into industry.

“The programme supports the objectives of the UK Industrial Strategy and the University’s Engineering Innovation Centre (EIC) to increase industry relevant research and applications linked to key local specialisms. Given that Lancashire represents the fourth largest aerospace cluster in the world, there is perhaps no better place to be developing next generation technologies for the UK aerospace industry.”

Previous graphene developments at UCLan have included the world’s first flight of a graphene skinned wing and the launch of a specially designed graphene-enhanced capsule into near space using high altitude balloons.

UCLan engineering students have been involved in the hands-on project, helping build Juno on the Preston Campus.

Haydale supplied much of the material and all the graphene used in the aircraft. Ray Gibbs, Chief Executive Officer, said: “We are delighted to be part of the project team. Juno has highlighted the capability and benefit of using graphene to meet key issues faced by the market, such as reducing weight to increase range and payload, defeating lightning strike and protecting aircraft skins against ice build-up.”

David Bailey Chief Executive of the North West Aerospace Alliance added: “The North West aerospace cluster contributes over £7 billion to the UK economy, accounting for one quarter of the UK aerospace turnover. It is essential that the sector continues to develop next generation technologies so that it can help the UK retain its competitive advantage. It has been a pleasure to support the Engineering Innovation Centre team at the University in developing the world’s first full graphene skinned aircraft.”

The Juno project team represents the latest phase in a long-term strategic partnership between the University and a range of organisations. The partnership is expected to go from strength to strength following the opening of the £32m EIC facility in February 2019.

The next step is to fly Juno and conduct further tests over the next two months.

Next item, a new carbon material.

Schwarzite

I love watching this gif of a schwarzite,

The three-dimensional cage structure of a schwarzite that was formed inside the pores of a zeolite. (Graphics by Yongjin Lee and Efrem Braun)

An August 13, 2018 news item on Nanowerk announces the new carbon structure,

The discovery of buckyballs [also known as fullerenes, C60, or buckminsterfullerenes] surprised and delighted chemists in the 1980s, nanotubes jazzed physicists in the 1990s, and graphene charged up materials scientists in the 2000s, but one nanoscale carbon structure – a negatively curved surface called a schwarzite – has eluded everyone. Until now.

University of California, Berkeley [UC Berkeley], chemists have proved that three carbon structures recently created by scientists in South Korea and Japan are in fact the long-sought schwarzites, which researchers predict will have unique electrical and storage properties like those now being discovered in buckminsterfullerenes (buckyballs or fullerenes for short), nanotubes and graphene.

An August 13, 2018 UC Berkeley news release by Robert Sanders, which originated the news item, describes how the Berkeley scientists and the members of their international  collaboration from Germany, Switzerland, Russia, and Italy, have contributed to the current state of schwarzite research,

The new structures were built inside the pores of zeolites, crystalline forms of silicon dioxide – sand – more commonly used as water softeners in laundry detergents and to catalytically crack petroleum into gasoline. Called zeolite-templated carbons (ZTC), the structures were being investigated for possible interesting properties, though the creators were unaware of their identity as schwarzites, which theoretical chemists have worked on for decades.

Based on this theoretical work, chemists predict that schwarzites will have unique electronic, magnetic and optical properties that would make them useful as supercapacitors, battery electrodes and catalysts, and with large internal spaces ideal for gas storage and separation.

UC Berkeley postdoctoral fellow Efrem Braun and his colleagues identified these ZTC materials as schwarzites based of their negative curvature, and developed a way to predict which zeolites can be used to make schwarzites and which can’t.

“We now have the recipe for how to make these structures, which is important because, if we can make them, we can explore their behavior, which we are working hard to do now,” said Berend Smit, an adjunct professor of chemical and biomolecular engineering at UC Berkeley and an expert on porous materials such as zeolites and metal-organic frameworks.

Smit, the paper’s corresponding author, Braun and their colleagues in Switzerland, China, Germany, Italy and Russia will report their discovery this week in the journal Proceedings of the National Academy of Sciences. Smit is also a faculty scientist at Lawrence Berkeley National Laboratory.

Playing with carbon

Diamond and graphite are well-known three-dimensional crystalline arrangements of pure carbon, but carbon atoms can also form two-dimensional “crystals” — hexagonal arrangements patterned like chicken wire. Graphene is one such arrangement: a flat sheet of carbon atoms that is not only the strongest material on Earth, but also has a high electrical conductivity that makes it a promising component of electronic devices.

schwarzite carbon cage

The cage structure of a schwarzite that was formed inside the pores of a zeolite. The zeolite is subsequently dissolved to release the new material. (Graphics by Yongjin Lee and Efrem Braun)

Graphene sheets can be wadded up to form soccer ball-shaped fullerenes – spherical carbon cages that can store molecules and are being used today to deliver drugs and genes into the body. Rolling graphene into a cylinder yields fullerenes called nanotubes, which are being explored today as highly conductive wires in electronics and storage vessels for gases like hydrogen and carbon dioxide. All of these are submicroscopic, 10,000 times smaller than the width of a human hair.

To date, however, only positively curved fullerenes and graphene, which has zero curvature, have been synthesized, feats rewarded by Nobel Prizes in 1996 and 2010, respectively.

In the 1880s, German physicist Hermann Schwarz investigated negatively curved structures that resemble soap-bubble surfaces, and when theoretical work on carbon cage molecules ramped up in the 1990s, Schwarz’s name became attached to the hypothetical negatively curved carbon sheets.

“The experimental validation of schwarzites thus completes the triumvirate of possible curvatures to graphene; positively curved, flat, and now negatively curved,” Braun added.

Minimize me

Like soap bubbles on wire frames, schwarzites are topologically minimal surfaces. When made inside a zeolite, a vapor of carbon-containing molecules is injected, allowing the carbon to assemble into a two-dimensional graphene-like sheet lining the walls of the pores in the zeolite. The surface is stretched tautly to minimize its area, which makes all the surfaces curve negatively, like a saddle. The zeolite is then dissolved, leaving behind the schwarzite.

soap bubble schwarzite structure

A computer-rendered negatively curved soap bubble that exhibits the geometry of a carbon schwarzite. (Felix Knöppel image)

“These negatively-curved carbons have been very hard to synthesize on their own, but it turns out that you can grow the carbon film catalytically at the surface of a zeolite,” Braun said. “But the schwarzites synthesized to date have been made by choosing zeolite templates through trial and error. We provide very simple instructions you can follow to rationally make schwarzites and we show that, by choosing the right zeolite, you can tune schwarzites to optimize the properties you want.”

Researchers should be able to pack unusually large amounts of electrical charge into schwarzites, which would make them better capacitors than conventional ones used today in electronics. Their large interior volume would also allow storage of atoms and molecules, which is also being explored with fullerenes and nanotubes. And their large surface area, equivalent to the surface areas of the zeolites they’re grown in, could make them as versatile as zeolites for catalyzing reactions in the petroleum and natural gas industries.

Braun modeled ZTC structures computationally using the known structures of zeolites, and worked with topological mathematician Senja Barthel of the École Polytechnique Fédérale de Lausanne in Sion, Switzerland, to determine which of the minimal surfaces the structures resembled.

The team determined that, of the approximately 200 zeolites created to date, only 15 can be used as a template to make schwarzites, and only three of them have been used to date to produce schwarzite ZTCs. Over a million zeolite structures have been predicted, however, so there could be many more possible schwarzite carbon structures made using the zeolite-templating method.

Other co-authors of the paper are Yongjin Lee, Seyed Mohamad Moosavi and Barthel of the École Polytechnique Fédérale de Lausanne, Rocio Mercado of UC Berkeley, Igor Baburin of the Technische Universität Dresden in Germany and Davide Proserpio of the Università degli Studi di Milano in Italy and Samara State Technical University in Russia.

Here’s a link to and a citation for the paper,

Generating carbon schwarzites via zeolite-templating by Efrem Braun, Yongjin Lee, Seyed Mohamad Moosavi, Senja Barthel, Rocio Mercado, Igor A. Baburin, Davide M. Proserpio, and Berend Smit. PNAS August 14, 2018. 201805062; published ahead of print August 14, 2018. https://doi.org/10.1073/pnas.1805062115

This paper appears to be open access.

Nano-saturn

It’s a bit of a stretch but I really appreciate how the nanoscale (specifically a fullerene) is being paired with the second largest planet (the largest is Jupiter) in our solar system. (See Nola Taylor Redd’s November 14, 2012 article on space.com for more about the planet Saturn.)

From a June 8, 2018 news item on ScienceDaily,

Saturn is the second largest planet in our solar system and has a characteristic ring. Japanese researchers have now synthesized a molecular “nano-Saturn.” As the scientists report in the journal Angewandte Chemie, it consists of a spherical C(60) fullerene as the planet and a flat macrocycle made of six anthracene units as the ring. The structure is confirmed by spectroscopic and X-ray analyses.

A June 8, 2018  Wiley Publications press release (also on EurekAlert), which originated the news item, fills in some details,

Nano-Saturn systems with a spherical molecule and a macrocyclic ring have been a fascinating structural motif for researchers. The ring must have a rigid, circular form, and must hold the molecular sphere firmly in its midst. Fullerenes are ideal candidates for the nano-sphere. They are made of carbon atoms linked into a network of rings that form a hollow sphere. The most famous fullerene, C60, consists of 60 carbon atoms arranged into 5- and 6-membered rings like the leather patches of a classic soccer ball. The electrons in their double bonds, knows as the π-electrons, are in a kind of “electron cloud”, able to freely move about and have binding interactions with other molecules, such as a macrocycle that also has a “cloud” of π-electrons. The attractive interactions between the electron clouds allow fullerenes to lodge in the cavities of such macrocycles.

A series of such complexes has previously been synthesized. Because of the positions of the electron clouds around the macrocycles, it was previously only possible to make rings that surround the fullerene like a belt or a tire. The ring around Saturn, however, is not like a “belt” or “tire”, it is a very flat disc. Researchers working at the Tokyo Institute of Technology and Okayama University of Science (Japan) wanted to properly imitate this at nanoscale.

Their success resulted from a different type of bonding between the “nano-planet” and its “nano-ring”. Instead of using the attraction between the π-electron clouds of the fullerene and macrocycle, the team working with Shinji Toyota used the weak attractive interactions between the π-electron cloud of the fullerene and non- π-electron of the carbon-hydrogen groups of the macrocycle.

To construct their “Saturn ring”, the researchers chose to use anthracene units, molecules made of three aromatic six-membered carbon rings linked along their edges. They linked six of these units into a macrocycle whose cavity was the perfect size and shape for a C60 fullerene. Eighteen hydrogen atoms of the macrocycle project into the middle of the cavity. In total, their interactions with the fullerene are enough to give the complex enough stability, as shown by computer simulations. By using X-ray analysis and NMR spectroscopy, the team was able to prove experimentally that they had produced Saturn-shaped complexes.

Here’s an illustration of the ‘nano-saturn’,

Courtesy: Wiley Publications

Here’s a link to and a citation for the paper,

Nano‐Saturn: Experimental Evidence of Complex Formation of an Anthracene Cyclic Ring with C60 by Yuta Yamamoto, Dr. Eiji Tsurumaki, Prof. Dr. Kan Wakamatsu, Prof. Dr. Shinji Toyota. Angewandte Chemie https://doi.org/10.1002/anie.201804430 First published: 30 May 2018

This paper is behind a paywall.

Psst: secret marriage … Buckyballs and Graphene get together!

A March 1, 2018 news item on Nanowerk announces  a new coupling,

Scientists combined buckyballs, [also known as buckminsterfullerenes, fullerenes, or C60] which resemble tiny soccer balls made from 60 carbon atoms, with graphene, a single layer of carbon, on an underlying surface. Positive and negative charges can transfer between the balls and graphene depending on the nature of the surface as well as the structural order and local orientation of the carbon ball. Scientists can use this architecture to develop tunable junctions for lightweight electronic devices.

The researchers have made this illustration of their work available,

Researchers are developing new, lightweight electronics that rapidly conduct electricity by covering a sheet of carbon (graphene) with buckyballs. Electricity is the flow of electrons. On these lightweight structures, electrons as well as positive holes (missing electrons) transfer between the balls and graphene. The team showed that the crystallinity and orientation of the balls, as well as the underlying layer, affected this charge transfer. The top image shows a calculation of the charge density for a specific orientation of the balls on graphene. The blue represents positive charges, while the red is negative. The bottom image shows that the balls are in a close-packed structure. The bright dots correspond to the projected images of columns of buckyball molecules. Courtesy: US Department of Energy Office of Science

A February 28, 2018 US Department of Energy (DoE) Office of Science news release, which originated the news item, provides more detail,

The Impact

Fast-moving electrons and their counterpart, holes, were preserved in graphene with crystalline buckyball overlayers. Significantly, the carbon ball provides charge transfer to the graphene. Scientists expect the transfer to be highly tunable with external voltages. This marriage has ramifications for smart electronics that run longer and do not break as easily, bringing us closer to sensor-embedded smart clothing and robotic skin.

Summary

Charge transfer at the interface between dissimilar materials is at the heart of almost all electronic technologies such as transistors and photovoltaic devices. In this study, scientists studied charge transfer at the interface region of buckyball molecules deposited on graphene, with and without a supporting substrate, such as hexagonal boron nitride. They employed ab initio density functional theory with van der Waals interactions to model the structure theoretically. Van der Waals interactions are weak connections between neutral molecules. The team used high-resolution transmission electron microscopy and electronic transport measurements to characterize experimentally the properties of the interface. The researchers observed that charge transfer between buckyballs and the graphene was sensitive to the nature of the underlying substrate, in addition, to the crystallinity and local orientation of the buckyballs. These studies open an avenue to devices where buckyball layers on top of graphene can serve as electron acceptors and other buckyball layers as electron donors. Even at room temperature, buckyball molecules were orientationally locked into position. This is in sharp contrast to buckyball molecules in un-doped bulk crystalline configurations, where locking occurs only at low temperature. High electron and hole mobilities are preserved in graphene with crystalline buckyball overlayers. This finding has ramifications for the development of organic high-mobility field-effect devices and other high mobility applications.

Here’s a link to and a citation for the paper,

Molecular Arrangement and Charge Transfer in C60 /Graphene Heterostructures by Claudia Ojeda-Aristizabal, Elton J. G. Santos, Seita Onishi, Aiming Yan, Haider I. Rasool, Salman Kahn, Yinchuan Lv, Drew W. Latzke, Jairo Velasco Jr., Michael F. Crommie, Matthew Sorensen, Kenneth Gotlieb, Chiu-Yun Lin, Kenji Watanabe, Takashi Taniguchi, Alessandra Lanzara, and Alex Zettl. ACS Nano, 2017, 11 (5), pp 4686–4693 DOI: 10.1021/acsnano.7b00551 Publication Date (Web): April 24, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall.

R.I.P. Mildred Dresselhaus, Queen of Carbon

I’ve been hearing about Mildred Dresselhaus, professor emerita (retired professor) at the Massachusetts Institute of Technology (MIT), just about as long as I’ve been researching and writing about nanotechnology (about 10 years total* including the work for my master’s project with the almost eight years on this blog).

She died on Monday, Feb. 20, 2017 at the age of 86 having broken through barriers for those of her gender, barriers for her subject area, and barriers for her age.

Mark Anderson in his Feb. 22, 2017 obituary for the IEEE (Institute of Electrical and Electronics Engineers) Spectrum website provides a brief overview of her extraordinary life and accomplishments,

Called the “Queen of Carbon Science,” Dresselhaus pioneered the study of carbon nanostructures at a time when studying physical and material properties of commonplace atoms like carbon was out of favor. Her visionary perspectives on the sixth atom in the periodic table—including exploring individual layers of carbon atoms (precursors to graphene), developing carbon fibers stronger than steel, and revealing new carbon structures that were ultimately developed into buckyballs and nanotubes—invigorated the field.

“Millie Dresselhaus began life as the child of poor Polish immigrants in the Bronx; by the end, she was Institute Professor Emerita, the highest distinction awarded by the MIT faculty. A physicist, materials scientist, and electrical engineer, she was known as the ‘Queen of Carbon’ because her work paved the way for much of today’s carbon-based nanotechnology,” MIT president Rafael Reif said in a prepared statement.

Friends and colleagues describe Dresselhaus as a gifted instructor as well as a tireless and inspired researcher. And her boundless generosity toward colleagues, students, and girls and women pursuing careers in science is legendary.

In 1963, Dresselhaus began her own career studying carbon by publishing a paper on graphite in the IBM Journal for Research and Development, a foundational work in the history of nanotechnology. To this day, her studies of the electronic structure of this material serve as a reference point for explorations of the electronic structure of fullerenes and carbon nanotubes. Coauthor, with her husband Gene Dresselhaus, of a leading book on carbon fibers, she began studying the laser vaporation of carbon and the “carbon clusters” that resulted. Researchers who followed her lead discovered a 60-carbon structure that was soon identified as the icosahedral “soccer ball” molecular configuration known as buckminsterfullerene, or buckyball. In 1991, Dresselhaus further suggested that fullerene could be elongated as a tube, and she outlined these imagined objects’ symmetries. Not long after, researchers announced the discovery of carbon nanotubes.

When she began her nearly half-century career at MIT, as a visiting professor, women consisted of just 4 percent of the undergraduate student population.  So Dresselhaus began working toward the improvement of living conditions for women students at the university. Through her leadership, MIT adopted an equal and joint admission process for women and men. (Previously, MIT had propounded the self-fulfilling prophecy of harboring more stringent requirements for women based on less dormitory space and perceived poorer performance.) And so promoting women in STEM—before it was ever called STEM—became one of her passions. Serving as president of the American Physical Society, she spearheaded and launched initiatives like the Committee on the Status of Women in Physics and the society’s more informal committees of visiting women physicists on campuses around the United States, which have increased the female faculty and student populations on the campuses they visit.

If you have the time, please read Anderson’s piece in its entirety.

One fact that has impressed me greatly is that Dresselhaus kept working into her eighties. I featured a paper she published in an April 27, 2012 posting at the age of 82 and she was described in the MIT write up at the time as a professor, not a professor emerita. I later featured Dresselhaus in a May 31, 2012 posting when she was awarded the Kavli Prize for Nanoscience.

It seems she worked almost to the end. Recently, GE (General Electric) posted a video “What If Scientists Were Celebrities?” starring Mildred Dresselhaus,

H/t Mark Anderson’s obituary Feb. 22, 2017 piece. The video was posted on Feb. 8, 2017.

Goodbye to the Queen of Carbon!

*The word ‘total’ added on March 14, 2022.

Soccer balls with no resistance (superconductivity)

Known as a fullerene (also buckminsterfullerene, buckyballs, and/or C60), the soccer ball in question is helping scientists to better understand how to develop materials that are superconductive at room temperature. A Feb. 9, 2016 news item on Nanotechnology Now describes the latest in ‘soccer ball’ research,

Superconductors have long been confined to niche applications, due to the fact that the highest temperature at which even the best of these materials becomes resistance-free is minus 70 degrees Celsius. Nowadays they are mainly used in magnets for nuclear magnetic resonance tomographs, fusion devices and particle accelerators. Physicists from the Max Planck Institute for the Structure and Dynamics of Matter at the Center for Free-Electron Laser Science (CFEL) in Hamburg shone laser pulses at a material made up from potassium atoms and carbon atoms arranged in bucky ball structures. For a small fraction of a second, they found it to become superconducting at more than 100 degrees Kelvin – around minus 170 degrees Celsius. A similar effect was already discovered in 2013 by scientists of the same group in a different material, a ceramic oxide belonging to the family of so-called “cuprates”. As fullerenes have a relatively simple chemical structure, the researchers hope to be able to gain a better understanding of the phenomenon of light-induced superconductivity at high temperatures through their new experiments. Such insights could help in the development of a material which conducts electricity at room temperature without losses, and without optical excitation.

A Feb. 8, 2016 Max Planck Institute press release (also on EurekAlert but dated Feb. 9, 2016), which originated the news item, expands on the theme of superconductivity at room temperature,

Andrea Cavalleri, Director at the Max Planck Institute for the Structure and Dynamics of Matter, and his colleagues aim at paving the way for the development of materials that lose their electrical resistance at room temperature. Their observation that fullerenes, when excited with laser pulses, can become superconductive at minus 170 degrees Celsius, takes them a step closer to achieving this goal. This discovery could contribute to establishing a more comprehensive understanding of light-induced superconductivity, because it is easier to formulate a theoretical explanation for fullerenes than for cuprates. A complete explanation of this effect could, in turn, help the scientists to gain a better understanding of the phenomenon of high-temperature superconductivity and provide a recipe for an artificial superconductor that conducts electricity without resistance losses at room temperature.

In 2013, researchers from Cavalleri’s group demostrated that under certain conditions it may be possible for a material to conduct electricity at room temperature without resistance loss. A ceramic oxide belonging to the family of cuprates was shown to become superconductive without any cooling for a few trillionths of a second when the scientists excited it using an infrared laser pulse. One year later, the Hamburg-based scientists presented a possible explanation for this effect.

They observed that, following excitation with the flash of light, the atoms in the crystal lattice change position. This shift in position persists as does the superconducting state of the material. Broadly speaking, the light-induced change in the structure clears the way for the electrons so that they can move through the ceramic without losses. However, the explanation is very dependent on the highly specific crystalline structure of cuprates. As the process was understood at the time, it could have involved a phenomenon that only arises in this kind of materials.

The researchers have included in the press release an image illustrating the latest work being described in the press release excerpt which follows this,

Intense laser flashes remove the electrical resistance of a crystal layer of the alkali fulleride K3C60, a football-like molecule containing 60 carbon atoms. This is observed at temperatures at least as high as minus 170 degrees Celsius. © J.M. Harms/MPI for the Structure and Dynamics of Matter

Intense laser flashes remove the electrical resistance of a crystal layer of the alkali fulleride K3C60, a football-like molecule containing 60 carbon atoms. This is observed at temperatures at least as high as minus 170 degrees Celsius.
© J.M. Harms/MPI for the Structure and Dynamics of Matter

The press release goes on to provide some technical details about the most recent research,

The team headed by Cavalleri therefore asked themselves whether light could also break the electrical resistance of more traditional superconductors, the physics of which is better understood. The researchers from the Max Planck Institute for the Structure and Dynamics of Matter, among which Daniele Nicoletti and Matteo Mitrano, have now hit the jackpot using a substance that is very different to cuprates: the fulleride K3C60, a metal composed of so-called Buckminster fullerenes. These hollow molecules consist of 60 carbon atoms which bond in the shape of a football: a sphere comprising pentagons and hexagons. With the help of intercalated positively charged potassium ions, which work like a kind of cement, the negatively charged fullerenes stick to each other to form a solid. This so-called alkali fulleride is a metal which becomes superconductive below a critical temperature of around minus 250 degrees Celsius.

The researchers then irradiated the alkali fulleride with infrared light pulses of just a few billionths of a microsecond and repeated their experiment for a range of temperatures between the critical temperature and room temperature. They set the frequency of the light source so that it excited the fullerenes to produce vibrations. This causes the carbon atoms to oscillate in such a way that the pentagons in the football expand and contract. It was hoped that this change in the structure could generate transient superconductivity at high temperatures in a similar way to the process in cuprates.

To test this, the scientists irradiated the sample with a second light pulse at the same time as the infrared pulse, albeit at a frequency in the terahertz range. The strength at which this pulse is reflected indicates the conductivity of the material to the researchers, meaning how easily electrons move through the alkali fulleride. The result here was an extremely high conductivity. “We are pretty confident that we have induced superconductivity at temperatures at least as high as minus 170 degrees Celsius,” says Daniele Nicoletti. This means that the experiment in Hamburg presents one of the highest ever-observed critical temperatures outside of the material class of cuprates.

“We are now planning to carry out other experiments which should enable us to reach a more detailed understanding of the processes at work here,” says Nicoletti. What they would like to do next is analyze the crystal structure during excitation with the infrared light. As was previously the case with the cuprate, this should help to explain the phenomenon. The researchers would then like to irradiate the material with light pulses that last much longer. “Although this is technically very complicated, it could extend the lifetime of superconductivity, making it potentially relevant for applications,” concludes Nicoletti.

Here’s a link to and a citation for the paper,

Possible light-induced superconductivity in K3C60 at high temperature by M. Mitrano, A. Cantaluppi, D. Nicoletti, S. Kaiser, A. Perucchi, S. Lupi, P. Di Pietro, D. Pontiroli, M. Riccò, S. R. Clark, D. Jaksch, & A. Cavalleri. Nature (2016) doi:10.1038/nature16522 Published online 08 February 2016

This paper is behind a paywall.

University of New Brunswick (Canada), ‘sun in a can’, and buckyballs

Cutting the cost for making solar cells could be a step in the right direction for more widespread adoption. At any rate, that seems to be the motivation for Dr. Felipe Chibante of the University of New Brunswick  and his team as they’ve worked for the past three years or so on cutting production costs for fullerenes (also known as, buckminsterfullerenes, C60, and buckyballs). From a Dec. 23, 2015 article by Michael Tutton for Canadian Press,

A heating system so powerful it gave its creator a sunburn from three metres away is being developed by a New Brunswick engineering professor as a method to sharply reduce the costs of making the carbon used in some solar cells.

Felipe Chibante says his “sun in a can” method of warming carbon at more than 5,000 degrees Celsius helps create the stable carbon 60 needed in more flexible forms of photovoltaic panels.

Tutton includes some technical explanations in his article,

Chibante and senior students at the University of New Brunswick created the system to heat baseball-sized lumps of plasma — a form of matter composed of positively charged gas particles and free-floating negatively charged electrons — at his home and later in a campus lab.

According to a May 22, 2012 University of New Brunswick news release received funding of almost $1.5M from the Atlantic Canada Opportunities Agency for his work with fullerenes,

Dr. Felipe Chibante, associate professor in UNB’s department of chemical engineering, and his team at the Applied Nanotechnology Lab received nearly $1.5 million to lower the cost of fullerenes, which is the molecular form of pure carbon and is a critical ingredient for the plastic solar cell market.

Dr. Chibante and the collaborators on the project have developed fundamental synthesis methods that will be integrated in a unique plasma reactor to result in a price reduction of 50-75 per cent.

Dr. Chibante and his work were also featured in a June 10, 2013 news item on CBC (Canadian Broadcasting Corporation) news online,

Judges with the New Brunswick Innovation Fund like the idea and recently awarded Chibante $460,000 to continue his research at the university’s Fredericton campus.

Chibante has a long history of working with fullerenes — carbon molecules that can store the sun’s energy. He was part of the research team that discovered fullerenes in 1985 [the three main researchers at Rice University, Texas, received Nobel Prizes for the work].

He says they can be added to liquid, spread over plastic and shingles and marketed as a cheaper way to convert sunlight into electricity.

“What we’re trying to do in New Brunswick with the science research and innovation is we’re really trying to get the maximum bang for the buck,” said Chibante.

As it stands, fullerenes cost about $15,000 per kilogram. Chibante hopes to lower the cost by a factor of 10.

The foundation investment brings Chibante’s research funding to about $6.2 million.

Not everyone is entirely sold on this approach to encouraging solar energy adoption (from the CBC news item),

The owner of Urban Pioneer, a Fredericton [New Brunswick] company that sells alternative energy products, likes the concept, but doubts there’s much of a market in New Brunswick.

“We have conventional solar panels right now and they’re not that popular,” said Tony Craft.

“So I can’t imagine, like, when you throw something completely brand new into it, I don’t know how people are going to respond to that even, so it may be a very tough sell,” he said.

Getting back to Chibante’s breakthrough (from Tutton’s Dec. 23, 2015 article),

The 52-year-old researcher says he first set up the system to operate in his garage.

He installed optical filters to watch the melting process but said the light from the plasma was so intense that he later noticed a sunburn on his neck.

The plasma is placed inside a container that can contain and cool the extremely hot material without exposing it to the air.

The conversion technology has the advantage of not using solvents and doesn’t produce the carbon dioxide that other baking systems use, says Chibante.

He says the next stage is finding commercial partners who can help his team further develop the system, which was originally designed and patented by French researcher Laurent Fulcheri.

Chibante said he doesn’t believe the carbon-based, thin-film solar cells will displace the silicon-based cells because they capture less energy.

But he nonetheless sees a future for the more flexible sheets of solar cells.

“You can make fibres, you can make photovoltaic threads and you get into wearable, portable forms of power that makes it more ubiquitous rather than having to carry a big, rigid structure,” he said.

The researcher says the agreement earlier this month [Nov. 30 – Dec. 12, 2015] in Paris among 200 countries to begin reducing the use of fossil fuels and slow global warming may help his work.

By the way,  Chibante estimates production costs for fullerenes, when using his system, would be less that $50/kilogram for what is now the highest priced component of carbon-based solar cells.

There is another researcher in Canada who works in the field of solar energy, Dr. Ted Sargent at the University of Toronto (Ontario). He largely focuses on harvesting solar energy by using quantum dots. I last featured Sargent’s quantum dot work in a Dec. 9, 2014 posting.